Journal of Parasitic Diseases: Diagnosis and Therapy

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Background: Coccidiosis remains one of the most important infectious causes of digestive disorders in rabbits. The aim of this study was to evaluate in vitro anticoccidial and antioxidant activities of Psidium guajava extracts. Methods: Sporulation inhibition bioassay was used to evaluate the activity of Psidium guajava extracts on sporulation of Eimeria flavescens, Eimeria stiedae, Eimeria intestinalis and Eimeria magna oocysts and sporozoites. The set up was examined after 24 h and 48 h for the oocysticidal activities and after 12 h and 24 h for anti-sporozoidal activities. The antioxidant activity was determined by measuring FRAP (ferric reducing-antioxidant power), 1,1-diphenyl-2- picrylhydrazyl (DPPH) free radical scavenging and nitric oxide (NO) radical scavenging. The cytotoxicity of the most active extract was determined against animal cell lines fibroblast L929, HEPG2 and Hella cells using MTT assay. The impact of the toxicity was established by analysing the Selectivity Index (SI) values. Results: The highest efficacy of tested plant extracts was recorded after 24 h, which varied according to different concentrations of the tested extracts. The highest efficacy was 88.67 ± 2.52% at the concentration of 30 mg/ml of the methanolic extract against E. intestinalis. Most extracts including the aqueous extract exhibited good anti-sporozoidal activities against E. flavescens, E. stiedae, E. intestinalis and E. magna sporozoites at 1000 µg/ml. The highest viability inhibitory percentage was 97.00 ± 1.73% at a concentration of 1000 µg/ml of P. guajava methanolic extract against E. intestinalis sporozoites. These results also showed that methanolic and Ethyl Acetate extract, possessed strong antioxidant activities (IC50<20 µg/ml). The methanolic extract of P. guajava exhibited CC50 of>30 µg/ml against selected cell lines, suggesting that the compounds are not toxic. Phytochemical screening of the most active extract showed presence of alkaloids, flavonoids, saponins and phenols. Conclusion: These results provide confirmation to the usage of Psidium guajava against coccidioses by Agricultural farmers in Cameroon.